The Times' education editor Tony Halpin tells how Prof David Jesson (York) has tracked the progress of 28,000 children who scored highest in English and Maths at age 11 (about the top 5 percent). About 11,800 went on to selective grammar schools or high achievement comprehensives, and 16,500 went on to lower quality schools.

Professor Jesson found that success rates declined in line with the numbers of bright children in a school, and dipped sharply when there were fewer than five. Where 20 pupils from the most able 5 per cent were clustered together in a year group, each achieved an average of nearly seven GCSE passes at A* and A grade last year. But where there was just one child from this group in a school, he or she passed fewer than four GCSEs at these grades.

This backs up the intuitive view that bright children encourage each other. At grammar schools competition and co-operation sit happily together. Children try to out-score each other, but often help their friends with homework and discus their work with their rivals. If our concern is to bring out the potential in every child, putting bright children to spur each other on seems an obvious way to set about it.

But there are those who argue that selective schools 'cream off' the talented children, leaving other schools without their beneficial effect. This outlook seems to treat bright children as some kind of scarce national resource to be shared out equally and fairly, without regard to what it does to their own development. It might even be counter-productive, not only holding back the bright ones, but making the other children aware of their academic shortcomings, when they might otherwise have happily applied themselves to more vocational skills.

The study suggests that academic work is like sport, in that its participants achieve more when alongside a high-achieving peer group. If we want the best and brightest to benefit themselves and their communities, we should put them together.